The invention relates to umbilical plug retract mechanisms and, in particular, to retract mechanisms capable of protectively accomodating large shock excursions.
As is known, missiles such as those launched from submarines, customarily are carried in launching tubes or the like from which they are fired or launched by motors which generate launch-gas pressure. In conventional systems, the missles are supplied with electrical power both prior to and during their initial lift-off and, for this purpose, so-called umbilical plugs, physically connected to the missiles, carry the power. At a proper time, retract mechanisms are employed to disengage the plugs and draw them away from the rising
A difficult design problem for any shipboard launching system arises because of the need to protect the missiles from being damaged by underwater explosions or other like forces which, for example, may occur during an attack. Specifically, the ship's hull, in responding to the explosive force, must be allowed to move a certain distance without imparting its force to the missile. Such movements are known as shock excursions against which the missile must be effectively isolated.
The use of umbilical retract mechanisms creates a special shock excursion problem since these mechanisms not only are mounted in close proximity to the missile but also are physically connected to it through the plug itself and, unless precautions are taken, the connections can transmit the forces to the missile. In early designs, umbilical retract mechanisms were attached to a shock-isolated structure surrounding the missile and therefore did not have to accomodate shock excursions. In more recent designs, however, they are so mounted that the external shock force can be applied through their physical coupling. Also, these mechanisms generally have been composed of relatively rigid elements which, to minimize shock loading, have been designed either to slide, pivot or telescope in manners so as to absorb or accomodate a applied forces. With the larger excursions presently anticipated, they had to grow in size with the corresponding increase in the effective mass to be accomodated. The increased size itself produces problems particularly in submarine applications where space is at a premium.
It is therefore an object of the present invention to provide an umbilical retract mechanism capable of accomodating large shock excursions and of minimizing shock loading by the retract mechanism on the missile.
Another object is to provide such a retract mechanism which has an unusually small size and mass.
Other objects are to provide simpler and more compact mechanisms which requires less adjustment and which accomodate larger shock excursions then previously permitted.
In general, the invention utilizes a flexible wire as a retract mechanism. The wire is attached at one end to the missile and at the other to a moveable member which is driven by the launch-gas pressure of the blast-off in a direction capable of exerting a pulling force on the wire for retracting the plug. The arrangement further includes a stop member mounted on the launch tube in the path of travel of the plug for initially disengaging the plug to permit its retraction. The flexible line is provided with a slack or catenary portion to accomodate shock excursions and to assure that the plug is disengaged prior to its retraction.